The DNA Cytometry Consensus Conference will discuss and critically evaluate the current state of knowledge and usefulness of measurements of DNA content in the management of individual patients for the following organ sites: Breast, Colon and Rectum, Bladder, and Prostate. For each of these sites, the technique has been suggested to have clinical utility. Core groups of internationally recognized experts will review the published studies and pertinent recent unpublished results for each organ site. Results from comparable studies will be evaluated whenever possible using quantitative analysis. In other cases a qualitative expert consensus will be attempted. If no consensus can be reached, the critical studies necessary to validate the technique will be defined. one session will be devoted to defining the necessary uniformly recognized standards for specimen preparation, flow or image cytometry technique, data analysis and interpretation of results. The primary objectives of the conference are to: 1) Provide a forum in which key international experts can examine in detail the clinical utility of DNA cytometry in solid tumors of the breast, colon and rectum, bladder, and prostate. 2) Reach a consensus on the clinical utility of DNA cytometry for the above organ sites. 3) Identify areas in which results are insufficient to reach a consensus and define the critical experiments required to reach a consensus. 4) Establish guidelines for specimen collection and preparation, standardization, data analysis, and interpretation, which are necessary to evaluate and to assure comparability of studies. 5) Publish the resulting consensus statements in appropriate journals to provide guidelines for the use of DNA cytometry in routine clinical practice.